If you have used CalDAV calendars on Mozilla Lightning/Sunbird, then the eM Client configuration is quite different, but simple.

To add a CalDAV account to eM Client

1. Go to Tools → Accounts
2. Click New Account…
3. Open the Calendar section and click on CalDAV
4. Press Next
5. In the Account Address URL box, type the base URL of your VPOP3's Webmail, followed by calendar/<username>/. Note that the username is case sensitive and must be exactly as it is defined in VPOP3. So, for the calendars for the Postmaster user, enter something like http://192.168.1.1:5108/calendar/Postmaster/.
6. In the User name box, type the VPOP3 account user name
7. In the Password box, type the VPOP3 account password (case sensitive)
8. Press Next
9. In the Account name box type a name you use to refer to this calendar
10. Press Next
11. Press Finish
12. Press OK

The calendars should now appear in the left column of the Calendar section in eM Client. Note that if the user has several calendars (in VPOP3 Enterprise) then all the calendars will be shown.